''Acaena'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of about 60 species of mainly

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

, creeping

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

perennial plants A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also widel ...

and

subshrub A subshrub (Latin ''suffrutex'') or dwarf shrub is a short shrub, and is a woody plant. Prostrate shrub is a related term. "Subshrub" is often used interchangeably with "bush".Jackson, Benjamin, Daydon; A Glossary of Botanic Terms with their Der ...

s in the family

Rosaceae Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are ''Alchemilla'' (270), ''Sorbus ...

native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entert ...

mainly to the Southern Hemisphere, notably New Zealand, Australia and South America, but with a few species extending into the Northern Hemisphere, north to Hawaii ('' A. exigua'') and California ('' A. pinnatifida''). The

leaves A leaf (plural, : leaves) is any of the principal appendages of a vascular plant plant stem, stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", wh ...

are alternate, long, and pinnate or nearly so, with 7–21 leaflets. The

flower A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

s are produced in a tight globose nflorescence in diameter, with no petals. The

fruit In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...

is also a dense ball of many

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

s; in many (but not all) species the seeds bear a barbed arrowhead point, the seedhead forming a burr which attaches itself to animal fur or feathers for dispersal. Several ''Acaena'' species in New Zealand are known by the common name bidibid. The word is written variously ''bidi-bidi'', ''biddy-biddy'', ''biddi-biddi'', ''biddi-bid'' and a number of other variations. These names are the English rendition of the original Māori name of ''piripiri''. The plant is also called the New Zealand burr. The species ''

Acaena microphylla ''Acaena microphylla'', the bidibid or piripiri, and outside New Zealand, New Zealand-bur, is a small herbaceous, prostrate perennial flowering plant in the rose family Rosaceae, native to both the North and South Islands of New Zealand. The ...

'' has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

Etymology

The generic name ''Acaena'' is derived from the Greek "akaina" (thorn), referring to the spiny

hypanthium In angiosperms, a hypanthium or floral cup is a structure where basal portions of the calyx, the corolla, and the stamens form a cup-shaped tube. It is sometimes called a floral tube, a term that is also used for corolla tube and calyx tube. It ...

Species

Plants of the World Online Plants of the World Online (POWO) is an online database published by the Royal Botanic Gardens, Kew. It was launched in March 2017 with the ultimate aim being "to enable users to access information on all the world's known seed-bearing plants by ...

accepted the following species: *''

Acaena agnipila ''Acaena'' is a genus of about 60 species of mainly evergreen, creeping herbaceous perennial plants and subshrubs in the family Rosaceae, native mainly to the Southern Hemisphere, notably New Zealand, Australia and South America, but with a ...

'' *''

Acaena alpina ''Acaena alpina'' is a perennial shrub of the genus ''Acaena'' known for its hardiness and durability. ''A. alpina'' is found throughout central Chile and Argentina. It can withstand a wide range of climates, including that of the Andes, where i ...

'' *''

Acaena anserinifolia ''Acaena'' is a genus of about 60 species of mainly evergreen, creeping herbaceous perennial plants and subshrubs in the family Rosaceae, native mainly to the Southern Hemisphere, notably New Zealand, Australia and South America, but with a ...

'' *''

Acaena antarctica ''Acaena antarctica'' is a small herbaceous plant in the Rosaceae family native to Argentina, Chile and the Falkland Islands. Taxonomy and naming ''Acaena antarctica'' was first formally described in 1846 by Joseph Dalton Hooker. Kew holds s ...

'' *''

Acaena argentea ''Acaena'' is a genus of about 60 species of mainly evergreen, creeping herbaceous perennial plants and subshrubs in the family Rosaceae, native mainly to the Southern Hemisphere, notably New Zealand, Australia and South America, but with a ...

'' *''

Acaena boliviana ''Acaena'' is a genus of about 60 species of mainly evergreen, creeping herbaceous perennial plants and subshrubs in the family Rosaceae, native mainly to the Southern Hemisphere, notably New Zealand, Australia and South America, but with a ...

'' *''

Acaena buchananii ''Acaena'' is a genus of about 60 species of mainly evergreen, creeping herbaceous perennial plants and subshrubs in the family Rosaceae, native mainly to the Southern Hemisphere, notably New Zealand, Australia and South America, but with a few ...

'' *''

Acaena caesiiglauca ''Acaena caesiiglauca'' (common name: glaucous pirri-pirri-bur or silver-leafed New Zealand burr) is a species of ''Acaena ''Acaena'' is a genus of about 60 species of mainly evergreen, creeping herbaceous perennial plants and subshrubs i ...

'' – glaucous pirri-pirri-bur *'' Acaena caespitosa'' *'' Acaena confertissima'' *'' Acaena cylindristachya'' *'' Acaena dumicola'' (

South Island The South Island, also officially named , is the larger of the two major islands of New Zealand in surface area, the other being the smaller but more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman ...

of New Zealand) *'' Acaena echinata'' – sheep's burr *''

Acaena elongata ''Acaena'' is a genus of about 60 species of mainly evergreen, creeping herbaceous perennial plants and subshrubs in the family Rosaceae, native mainly to the Southern Hemisphere, notably New Zealand, Australia and South America, but with a f ...

'' *'' Acaena emittens'' (

North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...

of New Zealand) *'' Acaena eupatoria'' *''

Acaena exigua ''Acaena exigua'' is an extinct species of flowering plant in the rose family known by the common name liliwai. It was endemic to Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Oce ...

'' – ''liliwai'' (

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...

) *'' Acaena fissistipula'' *'' Acaena fuscescens'' *'' Acaena glabra'' *'' Acaena hirsutula'' *'' Acaena inermis'' *'' Acaena integerrima'' *'' Acaena juvenca'' (New Zealand) *'' Acaena latebrosa'' *'' Acaena leptacantha'' *'' Acaena longiscapa'' *'' Acaena lucida'' *'' Acaena macrocephala'' *''

Acaena magellanica ''Acaena magellanica'', commonly called buzzy burr or greater burnet, is a species of flowering plant whose range includes the southern tip of South America and many subantarctic islands. Description ''Acaena magellanica'' is a perennial, mat-f ...

'' – greater burnet *'' Acaena masafuerana'' *''

'' – New Zealand-bur *'' Acaena minor'' *'' Acaena montana'' *'' Acaena myriophylla'' *''

Acaena novae-zelandiae ''Acaena novae-zelandiae'', commonly known as red bidibid, bidgee widgee, buzzy and piri-piri bur, is a small herbaceous, prostrate perennial, native to New Zealand, Australia and New Guinea, of the family Rosaceae. Description ''Acaena nov ...

'' – red bidibid (New Zealand) *''

Acaena ovalifolia ''Acaena ovalifolia'' is a species of flowering plant belonging to the family Rosaceae. Its native range is Western South America to Falkland Islands The Falkland Islands (; es, Islas Malvinas, link=no ) is an archipelago in the South ...

'' *''

Acaena ovina ''Acaena'' is a genus of about 60 species of mainly evergreen, prostrate shrub, creeping herbaceous plant, herbaceous perennial plants and subshrubs in the family Rosaceae, native plant, native mainly to the Southern Hemisphere, notably New Zeala ...

'' *'' Acaena pallida'' – sand bidibid *'' Acaena patagonica'' *''

Acaena pinnatifida ''Acaena pinnatifida'', the Argentinian biddy-biddy, is a species of perennial plant. Subspecies ''Acaena pinnatifida'' is often discussed as comprising several varieties. These include: *''Acaeana pinnatifida'' var. ''californica'' which is fo ...

'' – Argentinian biddy-biddy *'' Acaena platyacantha'' *'' Acaena poeppigiana'' *'' Acaena profundeincisa'' *'' Acaena pumila'' *'' Acaena rorida'' (North Island) *'' Acaena saccaticupula'' *'' Acaena sarmentosa'' *'' Acaena sericea'' *'' Acaena splendens'' *'' Acaena stangii'' *'' Acaena stricta'' *'' Acaena subincisa'' *'' Acaena tenera'' – lesser burnet *'' Acaena tesca'' (South Island) *'' Acaena torilicarpa'' *'' Acaena trifida''

Invasive species

Some species have been introduced accidentally to other areas, attached to

sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated s ...

wool Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool. As ...

, and have become

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

. ''

'', one of the bidibids from New Zealand, is the most commonly encountered species in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

, where it is often abundant on coastal sand dunes, crowding out native vegetation and creating an often painful nuisance with the barbed burrs. In California, '' A. pallida'', ''A. novae-zelandiae'' and '' A. anserinifolia'' are considered serious weeds."Weeds Sorted by Pest Rating"
CFDA.ca.gov

References

External links

Jepson Manual TreatmentUSDA Plants ProfileLandcare Research New Zealand
{{Taxonbar, from=Q1327017 Pantropical flora Rosaceae genera